The feasibility of contact heat evoked potentials (CHEPs) in early detection of symptomatic diabetic distal symmetric polyneuropathy (DSP)

Background: Novel treatment for particular nerve damage in patients with DSP is not available. Methods to identify types of nerve damage are available but too sophisticated. Therefore, quick, convenient, inexpensive method that can be used to identify type of nerve damage in patients with DSP is needed.;Objective: To investigate the feasibility of using contact heat evoked potentials (CHEPs) as a detection tool for DSP.;Method: This study had 3 stages.;1st stage: It was a systematic review of published studies on the treatment effect of pain in adult with diabetic neuropathy. Randomised controlled trials comparing topically and orally administered drugs with a placebo were included. The primary outcome was 50% pain reduction.;2nd stage: It was a methodological research testing the reliability of CHEPs. Twenty-two healthy adults were recruited. CHEPs were recorded using a 64-channel EEG cap. The peak stimulating temperature of 51°C was applied to dorsum of foot and 10cm proximal to lateral malleolus.;3rd stage: It was a cross-sectional study. Thirteen healthy adults, 19 diabetic patients and 10 diabetic patients with lower limb symptoms were recruited. CHEPs were recorded at midline channels. The peak stimulating temperature of 51°C was applied to dorsum of foot and 10cm proximal to lateral malleolus.;Results:;1st stage: 25 out of 31 reports were included. Nearly 50% of patients with diabetic neuropathy had un-resolved pain.;2nd stage. The single measure intra-class coefficients for first negative peak - first positive peak amplitude N1 -P1 amplitude (N1-P1 amplitude) were 0.802 and 0.604 for stimulation of dorsum of foot and 10cm proximal to lateral malleolus respectively.;3rd stage: There was significant difference of N1-P1 amplitude among the three groups following stimulation of dorsum of foot (p = 0.028) and 10cm proximal to lateral malleolus (p = 0.006).;Discussion: There may be loss of AS nerve fibres in diabetic patients with lower limb symptoms as reflected by significant reduction in the N1-P1 amplitudes of CHEPs. The results were consistent with morphological studies on nerves of diabetic patients with DSP.;Conclusion: CHEPs may be used for early identification of Adelta nerve fibres damage in DSP.